The present invention concerns a contact arrangement for a battery cell of a galvanic battery.
Galvanic batteries which contain a corroding electrolyte must be so tightly sealed that the electrolyte cannot leak out of the cells under any circumstances of operation, thereby causing damage to the apparatus employing the battery as a source of energy. The most usual reason for leakage of electrolyte in galvanic batteries is inadequate sealing at the point where the negative current collector terminal passes through the layer of insulating material functioning as the case of the battery cell.
In the Finnish Patent Publication 49,090 (U.S. Pat. No. 4,060,670) a contact assembly is described that totally excludes any electrolyte leakage, said contact assembly being based on the idea that a rigid metal plate is an essential part both in the positive and in the negative current collector, which metal plate is placed inside the case of the battery cell and which is, at the point where a contact member passes through the case of the battery cell, coated with a tough insulating material tightly adhering to the inside face of the case. Electrically conductive contact to these metal plates connected to the electrodes has been achieved by means of springs placed outside the battery cell and passing through the case of the battery cell as well as through the said layer of sealing material, being pressed tightly against the said metal plates. This contact assembly is usable and reliable, but automation of the production of batteries based on this idea has proved difficult. Moreover, it has been noticed that, especially in the case of small batteries, this contact system requires an unduly